Museum workers who say they are “just scraping by” went on strike on Saturday, as a new pay structure saw their pay package slashed.

Frontline workers at the Royal Museum Greenwich (RMG), the charity which runs the Cutty Sark, the National Maritime Museum and the Royal Observatory, said the pay gap between top and bottom at the organisation made them feel undervalued.

Many sales and visiting assistants are paid the legal minimum wage of £7.50 an hour, while museum director Kevin Frewster earns around £140,000 a year.

Triss Spencer, a representative for the Prospect union and a worker at the Royal Maritime Museum for three years, said: “You’re talking about people who are just scraping by, a grand a month in London.

“We can’t go on like this, especially if we are expected to work more for less, that’s the big issue.

“If anybody who is one of the high earners were to live the life as a front of line staff member at the museum for a little time, the would probably be out here with us as well.”

The new contracts introduced by RMG last November meant workers lost their right to a 40-minute paid break, which works out to a loss of three weeks worth of pay a year, according to Prospect Union figures.

The window of their working hours was also increased from 9.30am-5.15pm to 8am-8pm.

Visitors and sales team leader Andrew Hughes, 35, said: “It’s difficult to come in and feel the work you do is valued when you have an extreme difference in pay from top to bottom.

“It makes me wonder whether the work I do is actually worth it.

“That is very difficult and very frustrating.

“I love working in museums and I love working here. It is one of the most fantastic places to work. But it’s a shame we have these frustrations.

“Unfortunately your salary does make a difference to your sense of purpose in a place and the work you do, so this is having a really big negative effect.”

The strikers hope this action will bring RMG representatives back to the negotiating table, and help them move towards being paid the London Living Wage. RMG staff are among the only museum staff in London who are not paid the London Living Wage – £10.20 an hour.

A spokeswoman for RMG said: “The dispute is about the imposition of new terms, specifically in the case of those taking industrial action, former visitor assistants, whose breaks were cut from three to two daily, in return for a three per cent addition to salary by way of compensation.

“Only some 20 to 30 staff remain in dispute and discussions continue with the Prospect Union. The Director’s remuneration has not featured previously in any discussions but all staff remuneration is paid under remits issued under the Public Sector Pay Policy.”